You can also make an HDR image from one single exposure if you have a camera that can shoot RAW images. These files have more luminosity information than a finished JPG and through HDR you can bring out some of it.

Three versions from the same RAW image

You simply make two or three versions of the image from your RAW editing software. One under exposed where you adjust for the highlights. One normal. And one over exposed where you adjust for the shadows. Then you use your HDR software to put them together and tonemap.

There are three main factors that influence the quality of a digital image. The resolution is probably the most common. How many megapixels is your camera? Then, we have the compression. If you compress an image to make a smaller file using the JPEG-system you will loose some quality.

The third factor is the so called dynamic range. Can you take care of the details in both the highlights and the shadows? Here’s an example. You have a scene where the sky is dramatic and interesting. But you also want some details on the ground. In the following image I adjusted for the sky. And as you can see the ground is only a silhouette.
So you need to let in more light. Open up the aperture or add some time to the exposure. Very nice scenery, but no dramatic sky. As the next image shows.
Seems like you can’t have it all. Or maybe you can? There are actually a couple of solutions. One of them is called HDR, or High Dynamic Range photography. To put it simple, you combine several exposures into one using some magic mathematics. And the good news is that you don’t need to understand much of the mathematics, there are several tools to make HDR images and you can use most digital cameras when shooting for HDR.

For the image in my example I actually shot three versions. One standard exposure, one with +2 stops and one with -2 stops. All the three exposures are loaded into the HDR software to make an image that will show both the dramatic sky and the forest.What do you need?
When you’re out in the field you need a digital camera that let you manually adjust the exposure value and a tripod or something to support the camera. The three exposures need to be identical. Or at least nearly identical. Some of the HDR software out there will try to adjust if you have moved the camera slightly between exposures.

When you get back you need a computer and some HDR software. I am using Photomatix Pro. Available for both Mac and Windows. For Mac you can also try the free DRI maker. It doesn’t make true HDR images, but will help you with that difficult dynamic range by combining several images in a different way.

And if this quick introduction was interesting you can go further by having a look at the HDR group on Flickr. Lots of examples, tips and links.

Vacation. Yes, in Norway most of us can enjoy about five weeks of vacation each year. Spending some of it during winter, but usually most during summer.

This time I’ve had fun in the mountains.

And what’s up on eirikso.com? I am working on a lot of details with my new design and my new host. But I also have a lot of interesting articles in my list of drafts. I am geeky enough to include some technology in my vacation. You can expect an article about navigation systems and how they’re excellent entertainment for your geeky kid.

And as some of you might have noticed already. An article about my recent experiments with HDR photography.

And of course a lot more. I’m not spending hours on redesign and a a new host because this blog will be less interesting in the coming months!